1. Field of the Invention
The present invention relates to a communication technique, and more particularly, to a technique for switching a communication device to be used in a ubiquitous environment where pluralities of communication devices, which are connectable to a communication network, exist in a neighborhood.
2. Description of the Related Art
In recent years, communication devices such as a personal computer, a cellular phone, an Internet appliance, etc., which are connectable to a global IP network such as the Internet, etc., have been rapidly increasing. Additionally, connecting means for connecting such a network and communication devices has diversified into an xDSL line, a CATV network, a LAN, a cellular communication network, etc. In the meantime, near field communication standards such as RFID (Radio Frequency Identification), an ad hoc network of a wireless LAN, etc., PLC (Power Line Communication), Bluetooth (registered trademark), Zigbee (registered trademark), UWB (Ultra Wide Band), and the like have been proposed as communication standards for implementing a communication between other communication devices existing in the neighborhood of one communication device. Communication devices, which support both a global IP communication function and a near field communication function, are expected to increase in the future.
In a future ubiquitous environment, a situation in which pluralities of such communication devices having a network connection function exist around a user is quite conceivable. For example, in a user home environment, appliances such as a personal computer, a telephone, a TV receiver, a stereo set, a PDA, a cellular phone, etc. can be cited as such communication devices. These communication devices individually have different properties in terms of the performance of a processor, a memory, etc., an input/output function such as a display, a touch panel, etc., an installed application, and the like. Accordingly, it is preferable that each communication device is freely cooperative with a peripheral communication device (hereinafter referred to as a neighboring communication device) according to a user's purpose (for example, a videophone conversation, or the like) and can effectively use the neighboring communication device. Additionally, a user should desire to continually utilize an application in use even if an available neighboring communication device changes due to a factor such as a user move, etc. To satisfy such a demand, a technique for making a communication device dynamically cooperate with a plurality of neighboring communication devices becomes essential to a future ubiquitous society.
As a technique related to cooperation with a neighboring communication device, for example, Document 1, International Application Publication Pamphlet under the PCT WO02/15630, proposes the “device seamless” technique for seamlessly switching a communication device used by a user according to a user move or a change in a communication environment. With this technique, for example, a communication that a user makes with a personal computer is switched to a cellular phone when the user goes out.
Additionally, Document 2, New Technology, Information Device Cooperative “Task Computing” supporting a ubiquitous society, Fujitsu Journal February/March issue (No. 278), 2005, Fujitsu Co., Ltd., discloses the “task computing” technique proposed by Fujitsu Laboratories Ltd. With this technique, neighboring devices are freely combined and used. For example, an image received with a cellular phone is displayed on a neighboring television.
Furthermore, as the technique related to the present invention, for example, Document 3, Japanese Published Unexamined Patent Application No. 2005-45330, discloses the technique for improving communication efficiency by controlling the transmission/reception timings of wireless communication modules of mutually different wireless communication methods.
With the “device seamless” technique disclosed by the above described Document 1, a seamless device uses only one device at one time. Therefore, the effect of device cooperation is restricted to the performance, the input/output function, and the network connection function of one device even in an environment where pluralities of devices are available. This problem is further described with reference to FIG. 1.
In FIG. 1, a user can use a cellular phone 1000 and a personal computer (PC) 2000 as communication devices, and utilizes a service rendered by a server 3000 with the use of these communication devices. Here, both a cellular communication network 1100 that the cellular phone 1000 uses for a communication, and an xDSL line 2100 that the PC 2000 uses for a communication are connected to an IP network 3100. Various types of data are exchanged with the server 3000 via the IP network 3100.
Considered is a case where a videophone communication service that the PC 2000 receives from the server 3000 is used by being switched to the cellular phone 1000 and where the voice input/output convenience is superior to the PC 2000 in this environment. An illustration on the left side of FIG. 1 shows a state before being switched, whereas an illustration on the right side of FIG. 1 shows a state after being switched.
In the videophone communication service, a user must exchange both a voice data packet 3001 and an image data packet 3002, which are communication packets, with the server 3000 by using a communication device. However, a seamless device uses only one device at one time with the above described device seamless technique. Therefore, processes for exchanging the voice data packet 3001 and the image data packet 3002 are switched from the PC 2000 to the cellular phone 1000 if a communication device is switched. Accordingly, a large display of the PC 2000, which is expected to provide a more satisfactory image quality than the cellular phone 1000 in the display of an image represented with the image data packet 3002, or the xDSL line 2100 that has a communication capacity that is higher than the cellular communication network 1100 cannot be effectively utilized.
In the meantime, with the “task computing” technique disclosed by the above described Document 2, a plurality of devices can be used at the same time. However, the use of a network connection made by a communication device existing in the neighborhood of a user is not taken into account. This problem is further described with reference to FIG. 2.
In FIG. 2, a cellular phone 1000, a PC 2000, a server 3000, a cellular communication network 1100, an xDSL line 2100, and an IP network 2100 are similar to those shown in FIG. 1.
With the “task computing” technique, the cellular phone 1000 can make the PC 2000 to execute a task for displaying an image represented with an image data packet 3002 on the large display of the PC 2000 by transferring the image data packet 3002 among a voice data packet 3001 and the image data packet 3002, which are transmitted from the server 3000, if communication device switching, which is similar to that described with reference to FIG. 1, is made. Also with this technique, however, the xDSL line 2100 available to the PC 2000 is not utilized, and a user can receive a videophone communication service only within the scope of a communication cost, a communication rate, the degree of network congestion, the quality of radio waves, and a QoS (Quality of Service) function, of cellular communication network 1100.
As described above, neither the “device seamless” technique nor the “task computing” technique enables a plurality of network resources across communication devices to be effectively utilized when communication devices comprising a global IP communication function exist in the neighborhood of a user.